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Conrad Hal Waddington's "Experiments on the Development of Chick and Duck Embryos, Cultivated in vitro," published in 1932 in Philosophical Transactions of the Royal Society of London, Series B, compares the differences in the development of birds and amphibians. Previous experiments focused on the self differentiation of individual tissues in birds, but Waddington wanted to study induction in greater detail. The limit to these studies had been the amount of time an embryo could be successfully cultivated ex vivo.

In the July 2007 issue of Nature, Keisuke Okita, Tomoko Ichisaka, and Shinya Yamanaka added to the new work on induced pluripotent stem cells (iPSCs) with their "Generation of Germline-Competent Induced Pluripotent Stem Cells" (henceforth abbreviated "Generation"). The authors begin the paper by noting their desire to find a method for inducing somatic cells of patients to return to a pluripotent state, a state from which the cell can differentiate into any type of tissue but cannot form an entire organism.

Through various studies developmental biologists have been able to determine that the muscles of the back, ribs, and limbs derive from somites. Somites are blocks of cells that contain distinct sections that diverge into specific types (axial or limb) of musculature and are an essential part of early vertebrate development. For many years the musculature of vertebrates was known to derive from the somites, but the exact developmental lineage of axial and limb muscle progenitor cells remained a mystery until Nicole Le Douarin and Charles P.

Somites are blocks of mesoderm that are located on either side of the neural tube in the developing vertebrate embryo. Somites are precursor populations of cells that give rise to important structures associated with the vertebrate body plan and will eventually differentiate into dermis, skeletal muscle, cartilage, tendons, and vertebrae. Somites also determine the migratory paths of neural crest cells and of the axons of spinal nerves.

The purpose of regenerative medicine, especially tissue engineering, is to replace damaged tissue with new tissue that will allow the body to resume normal function. The uniqueness of tissue engineering is that it can restore normal structure in addition to repairing tissue function, and is often accomplished using stem cells. The first type of tissue engineering using stem cells was hematopoietic stem cell transplantation (HSCT), a surgical procedure in which hematopoietic stem cells (HSCs) are infused into a host to treat a variety of blood diseases, cancers, and immunodeficiencies.

For Thomas Hunt Morgan clarity was of utmost importance. He was therefore frustrated with the many disparate, disconnected terms that were used to refer to similar, if not the same, regenerative processes within organisms. When Morgan wrote Regeneration in 1901 there had been many different terms developed and adopted by various investigators to describe their observations. As a result there were many inconsistencies making it difficult to discuss results comparatively and also making it more challenging to generalize. Defining terms was a priority for Morgan.

Richard A. Lockshin's 1963 PhD dissertation on cell death in insect metamorphosis was conducted under the supervision of Harvard insect physiologist Carroll M. Williams. Lockshin and Williams used this doctoral research as the basis for five articles, with the main title "Programmed Cell Death," that were published between 1964 and 1965 in the Journal of Insect Physiology. These articles examine the cytological processes, neuronal and endocrinal controls, and the influence of drugs on the mechanism of cell death observed in pupal muscle structures of the American silkmoth.

Translational developmental biology is a growing approach to studying biological phenomena that explicitly aims to develop medical therapies. When discussing the generation of new therapies it is often argued that they will emerge as a "translation" from "fundamental biology." Although translational research is not a new term, "translational developmental biology" has been steadily gaining popularity as discoveries in cell and developmental biology, particularly those involving stem cells, provide a basis for regenerative medicine.

On 20 November 2009 Democrat Barack Obama replaced Republican George W. Bush as president of the United States. Obama soon initiated changes to Bush's 2001 executive order concerning scientific research involving human stem cells. Stem cell research remains a controversial issue in the US. Some individuals consider it immoral to experiment with an embryo because they regard embryos as human beings from the moment of conception, while others believe stem cell research could lead to great scientific advancements.

In 1962 the journal Acta Biotheoretica published the final work of the biologist Edward Stuart Russell, a full eight years after his death. Entitled The Diversity of Animals: an Evolutionary Study, this short, unfinished manuscript on evolution received little recognition in the scientific presses despite both its technical discussion of adaptations in decapods (crabs, shrimp, etc.) and its different approach to evolutionary theory. The precise reason for this neglect is unclear.

In November 2007, Masato Nakagawa, along with a number of other researchers including Kazutoshi Takahashi, Keisuke Okita, and Shinya Yamanaka, published "Generation of Induced Pluripotent Stem Cells without Myc from Mouse and Human Fibroblasts" (abbreviated "Generation") in Nature. In "Generation," the authors point to dedifferentiation of somatic cells as an avenue for generating pluripotent stem cells useful for treating specific patients and diseases.

Bicoid is the protein product of a maternal-effect gene unique to flies of the genus Drosophila . In 1988 Christiane Nüsslein-Volhard identified bicoid as the first known morphogen . A morphogen is a molecule that determines the fate and phenotype of a group of cells through a concentration gradient across that developing region. The bicoid gradient, which extends across the anterior-posterior axis of Drosophila embryos, organizes the head and thorax.

Maternal consumption of alcohol (ethanol) during pregnancy can inhibit prenatal growth, resulting in fetuses that are small for gestational age. Those prenatal growth deficiencies can have lasting consequences for early childhood development and are often reflected by low weight and stature. Those alcohol-induced pre- and post-natal growth deficiencies ("failure to thrive") are among the abnormal developmental criteria used to identify Fetal Alcohol Syndrome (FAS). FAS is characterized by minor facial abnormalities and deficiencies of the central nervous system as well.

Embryogenesis is an intricate process that can easily be disrupted by means of teratogenic agents. Some of these agents target the embryonic period's "window of susceptibility," three to eight weeks after a pregnant woman's last menstruation, when the highest degree of sensitivity to embryonic cell differentiation and organ formation occurs. The embryonic period or critical period is when most organ systems form, whereas the fetal period, week eight to birth, involves the growth and modeling of the organ systems.

Teratomas are embryonal tumors that normally arise from germ cells and are typically benign. They are defined as being composed either of tissues that are foreign to the area in which they form, or of tissues that derive from all three of the germ layers. Malignant teratomas are known as teratocarcinomas; these cancerous growths have played a pivotal role in the discovery of stem cells. "Teratoma" is Greek for "monstrous tumor"; these tumors were so named because they sometimes contain hair, teeth, bone, neurons, and even eyes.

Nerve growth factor (NGF) is a signaling protein and growth factor implicated in a wide range of development and maintenance functions. NGF was discovered through a series of experiments in the 1950s on the development of the chick nervous system. Since its discovery, NGF has been found to act in a variety of tissues throughout development and adulthood. It has been implicated in immune function, stress response, nerve maintenance, and in neurodegenerative diseases.

The paper "Formation of Genetically Mosaic Mouse Embryos and Early Development of Lethal (t12/t12)-Normal Mosaics," by Beatrice Mintz, describes a technique to fuse two mouse embryos into a single embryo. This work was published in the Journal of Experimental Zoology in 1964. When two embryos are correctly joined before the 32-cell stage, the embryo will develop normally and exhibit a mosaic pattern of cells as an adult.

Wilhelm Roux was an influential figure in the early history of experimental embryology. Although he originally studied medicine, he was invited to be a Privatdozentur, or unsalaried lecturer, at the Anatomical Institute in Breslau (Wroclaw), Poland, in 1879. He spent the next ten years at this institute, working his way from Dozent to associate professor and finally, in 1889, to director for his own institute, Institut für Entwicklungsgeschichte, or Institute for Developmental History and Mechanics.

Although the concept of quickening was not developed initially by the Roman Catholic Church, much of their histories are intertwined. Quickening, the point at which a pregnant woman can first feel the movements of the growing embryo or fetus, has long been a pivotal moment in pregnancy. Historically, it has also been a pivotal moment for law and the Church in deciding the criminal and religious sanctions for women who intentionally procured an abortion.

On 20 January 2001, Republican George W. Bush was sworn in as the forty-third president of the United States, replacing Democrat William J. Clinton. During his eight years in office, Bush issued many executive orders, often altering previous policy. By signing Order 13435 on 22 June 2007, he changed how stem cell research would be performed in America.

Amniocentesis is a test used for prenatal diagnosis of inherited diseases, Rh incompatibility, neural tube defects, and lung maturity. Normally performed during the second trimester of a pregnancy, this invasive procedure allows the detection of health problems in the fetus as early as fifteen weeks gestation. Although amniocentesis does carry some significant risks, the medical community commonly accepts it as a safe and useful procedure.

The hanging drop tissue culture is a technique utilized in embryology and other fields to allow growth that would otherwise be restricted by the flat plane of culture dishes and also to minimize the surface area to volume ratio, slowing evaporation. The classic hanging drop culture is a small drop of liquid, such as plasma or some other media allowing tissue growth, suspended from an inverted watch glass. The hanging drop is then suspended by gravity and surface tension, rather than spreading across a plate.

John Hilton Edwards first described the symptoms of the genetic disorder known as Trisomy 18 - one of the most common forms of trisomy, which occurs when cells have an extra copy of a chromosome, in humans - in 1960. Trisomy 18, also known as Edwards Syndrome, occurs approximately once per 6000 live births and is second in frequency only to Trisomy 21, or Down's Syndrome, as an autosomal trisomy. Trisomy 18 causes substantial developmental problems in utero.

The 1986 US Supreme Court decision Bowen v. American Hospital Association rejected the federal government's use of Section 504 of the Rehabilitation Act of 1973 to intervene in a hospital's treatment for neonates born with severe congenital defects. This case set a precedent for the role of government involvement in cases where parents refused consent for care of disabled newborns.

In a case of first impression in the state of New York, the highest state court decided that a priori written agreement between progenitors of frozen embryos regarding the disposition of their "pre-zygotes" in the event of divorce is binding. By copying the general result arrived at by the Tennessee Supreme Court in Davis v. Davis in 1992, the New York court magnified the weight of authority in favor of upholding prior written agreements for in vitro fertilization practices.